tests: unlink libxl-driver.log

The libxlxml2domconfigtest causes a libxl-driver.log file to be created
which breaks make distchck if libxl is enabled. Delete the log file at
the end of the test.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

tests/libxlxml2domconfigtest.c

@@ -211,6 +211,8 @@ mymain(void)
     DO_TEST("multiple-ip");
     DO_TEST("fullvirt-cpuid");
 
+    unlink("libxl-driver.log");
+
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }